TWO BEADS FOR SAINT JUDE by Gene Woolsey, Colorado School of Mines THE FIRST BEAD: In a note of Rustagi and Doub [I], it was asserted that: "Whether it is a fighter airplane, a ship,or a tank, the basic structure of the optimal armor allocation decision process seems to be the same:. This statement was then followed by anexcellent formulation of the optimal armor allocation problem as a dynamic p r o g r a m for a tank. It was strongly implied that the same formulation, or a similar one, using dynamic p r o g r a m m i n g in any case could be extended to a ship or a plane. However, it should be considered that the optimal armoring of a fighter plane may introduce additional constraints to a level where dynamic programming may become computationally infeasible. For example, the w e i g h t distribution of even a few pounds of armor must be considered in the light of relative stresses and strains on the aeroplane as a whole. A d d i t i o n a l armor added to a plane will often require considerable redesign just to m a i n t a i n the p r e s e n t performance of the aircraft, or to drop its capability as little as possible. This redesign will then alter the formulation of the dynamic program, which then may generate a different p l a c e m e n t of armor, w h i c h then leads to redesign, which will then lead to ...... etc. As an afterthought we should also note that the relationships between the design characteristics are seldom (I) linear, nor even (2) separable, thus again casting some doubt as to the efficacy of dynamic programming for this application. Finally, one just might suspect that if a plane is armored tank, it just might fly like a tank. like a THE SECOND BEAD: W h e n one works in Canada, one rapidly discovers that O.R. is p r o n o u n c e d Operational Research and is a p r o f e s s i o n that o r i g i n a t e d in England during World--War II. Giving the E n g l i s h their due, there is also the story that the original operational research group was the first to discover the principle of the inverse data operator. This operator is used w h e n it is discovered that the wrong data has been taken for the model. Now let D -I be defined as the inverse data operator, and let WD be defined as a body of Wrong Data. The action of the inverse data--operator is to convert wrong data into the right data. In symbols, we have: D-i(WD) = RD. The necessary conditions for this o p e r a t o r to work is that the wrong data really implies the right data. The first known example took place in the celebrated study of o p t i m u m u t i l i z a t i o n of Spitfires and Hurricanes during the battle of Britain. W h e n e v e r a Spitfire or Hurricane returned to the aerodrome, careful note was made upon pads m a d e up for the purpose, as to where each bullet hole appeared upon the aircraft. This information was then m e t i c u l o u s l y d i a g r a m m e d and correlated. A d d i t i o n a l armor was then suggested on the basis of this data. The study e x p e r i e n c e d the D -I operator when an unnamed group captain noted that they were counting holes and making recommendations on the basis 0f the planes that returned. Gene Woolsey, (Capt. USAFR) i. J.S. Rustagi, and T.W. Doub, "Optimum D i s t r i b u t i o n of Armor," Operations Research, Vol. 18, pp. 559-562, 1970. Ii

/lp/association-for-computing-machinery/two-beads-for-saint-jude-dB661fGxBj